1. Field of the Invention
The present invention provides devices for the stabilization of the spinal column and, more particularly, to dynamic devices for the stabilization of the spinal column.
2. Background Information
A significant portion of the population suffers from spinal problems. Such spinal problems may be attributable to disease, trauma and/or other event. In the case of degenerative disc disease, spinal trauma and the like, such conditions are often painful and/or physically deforming. Depending on the situation, the pain and complications caused by these conditions may require that one or more vertebra, facet joints, and/or intervertebral discs be removed from the spinal column. In these procedures, bone fusion is a common treatment used to facilitate the realignment and/or fixation of the remaining spinal elements.
Currently, two types of systems or assemblies are utilized for securing and/or stabilizing one or more vertebrae in order to achieve bone fusion. One type of spine stabilizing assembly generally includes two posterior vertebral plates disposed longitudinally on either side of the spinous processes. Each plate is attached between adjacent vertebra using bone anchoring elements, such as bone screws. Together, the plates provide a rigid vertebral fixation.
Another type of spine stabilizing assembly generally includes two posterior vertebral rods disposed longitudinally on either side of the vertebrae (e.g. the spinous processes thereof). Like the plates, these rods are attached between adjacent vertebrae using appropriate bone anchoring devices to achieve rigid vertebral fixation.
These spine stabilizing assemblies are also used to correct spinal deformities such as scoliosis or the like. For this use, such spine stabilizing assemblies may have spine rods that span two or more vertebrae.
A drawback of rigid fixation relates to the loading that occurs on the stabilizing assemblies and especially on the anchoring sites during normal activity. These loads may result in loosening of the assembly from the vertebrae or even breaking of the assembly. Also, fusion subjects the non-fused spine elements to various stresses, particularly the remaining adjacent vertebrae and vertebral discs since these elements must accommodate different degrees of motion. Moreover, spinal fusion limits the range of a patient's motion.
Because of the drawbacks to rigid spine fixation systems, semi-rigid spine fixation systems have been proposed that aim to allow limited intervertebral movement for promoting bone fusion and/or reducing spine stress. These semi-rigid spine fixation systems, however, are far from effective and/or efficient.
There is thus a need for an improved semi-rigid spine stabilization device, assembly and/or system.
This need and others is accomplished through application of the principles of the subject invention and/or as embodied in one or more various forms and/or structures such as are shown and/or described herein.